How deep are your buddy's pockets and how long does he want these motors to last?

Safe way is to start 4-5psi and adjust up from there. If he is a balls to the wall guy that always has to be fastest I doubt he will take that approach though. Also if his drives are Bravos that is another consideration, its always nice to have reliability

I am running 4-5psi on my 502MPIs with B&M blowers. I run the 93 octane fuel. Plenty of "go" with long term reliability as well.

502 mpi's and B&M HUFFERS???? I gotta see this..Did you mount them like whipple does their side mounted set up ..

Right on top

Not getting into any debates but here is my opinion.
The 8-71's at -15% won't make any real heat to warrant chilling and losing idle quality. If it had a 256 blower with a higher rotor speed I would say chill it. BTW, what kind of boat are we dropping them in?
Is this a weekend pleasure boat, Jet or I/O?
Also what size heads?

speaking with mild a little whyle ago he said the boat their going in is a 38 cig flat deck..

looks good brutha

That looks sweet

I,m with bfm. 4lbs of boost, no chiller, and no thermostat.

What "loss of idle quality" are you talking about? My blown/injected/intercooled 509 will idle until the cows come home.
And yes, the injectors are on top of the blower.

PS, as to the original question, I run 7psi but only 8.2 SCR.